Single motor drive



' Aug. 23, 1932. F. w. HILD SINGLE MOTOR DRIVE Filed-Nov. 8. 1924 2 Sheets-Sheet l INVENTOR Fvvr/c a 17/74 ATTORNEY F. w. HILD S INGLE MOTOR DRIVE Aug. 23, 1932.

Filed Nov. 8. 1924 2 Sheets-Sheet 2 INVENTOR fic r/c [d 67/0 ATTORNEY 1 Patented Aug.f 23, .1932

UNITED STATES FBEDEBIC W. HILD, 01 L ANGELEB, CALIFORNIA.

SINGLE MOTOR DRIVE Application filed November 8, 1924, Serial No. 748,571.

' My invention relates to a differential mechanism, more particularly. to a device for automatically retrieving arotating member which is advanced in a given direction, such 5 device bein particularly applicable to earth boring mac ines utilized for oil well drilling. It is among the objects of my invention to provide a drive mechanism for earth boring machines which shall embody means for reg l ulating the feed of the cutting tool relative to the rate of the cutting action thereof in an advance or reverse direction.

. Another object of my invention is to provide means for reversing or retrieving the tool member from its advance direction of feeding when the rotary movement thereof is impeded to the extent of materially reducing its speed or preventing such rotatory movement altogethen It is another object of my invention to provide a drive mechanism for earth boring machines utilizing a single motor for performing the several functions of rotating and feeding the drill or cutting member and to provide automatic regulating means for go-ordinating the operation of the drill memer.

In. earth boring machines utilizing a rotatory cutting device, the cutter is secured to a work spindle or drill stem which extends it vertically in the hole being formed and through an opening in the rotary table, the portion associated with the rotary table being commonly termed the grief stem. -The drill stem is associated with a drum constituting part of a draw works which 'is .ufiilized in'hoi'sting'the drill and to regulate t e mem er is fed by gravity so that the pressureexerted on the cutting face of the tool may be varied by controlling the position of the drum member through a brake mechanism from zero to a pressure'corresponding to the entire weight of the drill and stem member. My present invention comprises a feeding device which regulates the feeding of the drill in accordance with'the resistance en: countered by the drill bit and which, in some cutting member encounters excessive resistressure on the drill bit. The cutting cases, functions to lift the drill when the.

ance and has a tendency to stall. This liftin action is a retrieving function which is e ected by a screw-and-nut mechanism associated with the main driving element.

In the accompanying drawings constituting a part hereof and in which like reference characters designate like parts: I

Figure 1 is a diagrammatic view of an earth boring device embodying the principles of my invention, and Y Fig. 2 is a similar view ofthe nut mocha nism connected to the grief stem.

Figs. 3' and 4 are views partially in section and partially in side elevation of the feed screw member and grief stem showing different means of securing them to effectadvancement of the drill, and

Figs. 5 and 6 areend views of the stem and screw shown in Figs. 3 and 4 respectively.

Referring to Fig. 1, the device therein illustratedcomprises a rotary table 1 having a worm wheel 2, formed integrally therewith 01'' secured thereto and a base plate 3 on which the head is mounted in a manner to permit rotatory movement thereof. The table 1 is provided witha rectangular opening 4 adapted to receive a correspondingly shaped drill stem 5 which has a slidin fit therewith and is adapted to movecoaxia ly in a vertical direction. A threaded sleeve member 6 having a rectangular opening 7, Fig. 2, is disposed around the drill stem below the rotary head and secured to the stem member in any suitable manner as by screw bolts. A worm gear 9 having a bearing member 10 is supported by a ball race 11 on a suitable support 12.

The worm gear 9 is provided with a threaded opening 13 adapted to engage the threaded screw sleeve 6.

The drill stem 5 and the feed screw 6 may be adjustably secured as shown in Figs. 3, 4, g

5 and 6. The. means utilized in Figs. 3' and 5 comprises .a 's lit nut 6a of conical shape having a threa e'd portion 65' for engaging the screw thread 5a of the stem 5. The thread of the screw 6 is right hand and that of the stem5 left hand to effect an interlock of the stem 5' and sleeve-6 when the latter is rotated in a right hand direction of rotation.

When the sleeve 6 has traversed the length of its thread in the gear 9, an adjustment is made by holding the stem against turning and reversing the direction of rotating the sleeve until it has withdrawn from the gear 9. In F i s. 4 and 6 a square stem 5 is shown with a slip 6a having serrated teeth (30 for holding the stem.

pair of worm shafts 14 and 15 having worms 16 and 17 are disposed in co-operative alignment with the worm gears 2 and 9, respectively, the worms 16 and 17 being in engagement with the teeth of the gear members. The shafts 14 and 15 are provided with cone pulleys 18 and 19, which pulleys are connected by a belt 20. The worm shaft 14 is connected to a motor shaft 21 of a drive motor 22 and the belt 20 is provided with a magnetic shifting device comprising a fork 23 adapted to engage the belt 20, having a plunger 24 supported by a coil spring 25 against a bracket 26, having an opening 27 therein through which the plunger 24 extends. The end of the plunger 24 constitutes the armature of a solenoid 28 which is electrically connected to the windings of the motor 22 in such a manner that the solenoid will be energized and de-energized in accordance with the cur rent fluctuations of the motor 22.

The lower end of the stem 5 terminates in a drill stem to which the cutting tool is secured and the upper portion is connected to the hoist cable of the draw works in the usual manner.

The operation of my device is briefly as follows: The motor 22 is energized to rotate the drive shaft 14 which by virtue of its worm gear connection to the drill table 1 effects rotating movement thereof and consequently revolves the grief stem 5 by virtue of its engagement with the table. The shaft 15 being operatively connected to the shaft 14 by the belt 20 rotates in the same direction as the former to effect rotating movement of the worm gear 9. The solenoid 28 of the shifting mechanism is wound so that the shifting member 23 will assume a neutral position for the normal torque characteristics of the motor 22 but when the drill member encounters such resistance as to produce an overload on the motor, the solenoid will actuate the plunger 24 of the shifter mechanism to increase or reduce the speed of the shaft 15.

The relative speeds of the shafts l4 and 15 must be such that the angular velocities of the worm gears 2 and 9 are such that the nut 6 will advance slightly in the direction of the cutting tool and when the latter encounters resistance in excess of the normal operating torque of the motor the solenoid 28 will function to shift the belt 20 along the cone pulleys to decrease the speed of the shaft 15 which will cause a retrieval of the screw sleeve 6 away from the work end of the drill thereby lifting the drill stem to permit the drill to free itself and prevent breakage of the cutting edge. When the motor torque is again normal, the shifting mechanism will automatically regulate the speeds of the drive shafts to again effect feeding of the drill memher in the direction of the work.

The feed-screw mechanism is thus automatically regulated to feed the drill and retrieve the same in accordance with the resistance encountered by the cutting tool depending upon the formation of the strata encountered in the drilling operation. The length of the feed screw 6 may be such as to provide a reasonable amount of advance feed for the cutting member between adjustments of the screw and drill stem, which will be necessary when the screw sleeve 6 has traversed its entire length.

It is evident from the foregoing description of my invention that an earth borin device embodying the principles herein set forth provides a simple and efiicient means for regulating the feed of the drill member in accordance with the rate of cutting speed and to retrieve the drill member in case of necessity to prevent breakage of the drill bit when the latter enters a relatively hard strata of rock and the like. My device further provides means for utilizing a single drive motor for the double function of rotating the drill member and regulate the feeding thereof and the screw mechanism and speed regulating device provides automatic regulation and co-ordination of the drill and feed mechanism.

Although I have described a specific embodiment of my invention, it will be obvious to those skilled in the art that various modifications may be made in the details of construction, in the arrangements of the several co-operating parts and in the manner of applying my mechanism to the various purposes for which it may be utilized without departing from the principles herein set forth.

I claim as my invention 1. The combination with a drill, of a mechanism having two driven members for respectively effecting rotational and longitudinal movement of said drill, a pair of cone pulleys respectively associated with said driven members, a motive device connected to one of said pulleys, a belt for connecting said pulleys, and means responsive to the load on said'motive device for shifting said belt along said cone pulleys.

2. The combination with a drill, of a mechanism having two driven members for respectively effecting rotational and longitudinal movement of said drill, a pair of co perating cone pulleys respectively connected to said driven members, an electric motor connected to one of said pulleys, a belt for connecting said pulleys, and a magnetic device responsive to the motor load for shifting said belt to var the speed ratio between said driven mem ers.

3. The combination with a rotary table and drill stem secured therein, of a drive mechanism therefor including an electric motor, a screw-and-nut mechanism for feeding said stem and separate magnetic means electrically interconnected with said motor and mechanical speed control means, controlled by said magnetic means, connected to said screw-andnut mechanism for regulating the speed and direction of feeding said stem as a function of the operating characteristics of said motor.

4. The combination with a rotary table and drill stem secured therein, of a drive mechanism therefor including an electric motor, a screw-threaded mechanism for feeding said stem, means connected to said drive mechanism for actuating said feed mecha' nism, a solenoid connected in the circuit of the motor and responsive to the load current of the motor, and means controlled by said solenoid for regula'tin the speed and direc tion of feeding of sai stern.

5. The combination with a rotary table and drill stem secured therein, a drive mechanism therefor, an electric motor for operating the drive mechanism, a screw-threaded mechanism for feeding said stem, means connected to the drive mechanism to also actuate the said feed mechanism from said motor, and an independent connecting means shifting de- Vice responsive to the load on the motor for automatically regulating the speed and direction of feeding said stem.

6. In a feed mechanism for cutting tools, the combination with a supporting structure and a tool spindle journalled therein, of a feed screw mounted on the spindle, a feed nut journalled on the sup orting structure in engagement with the feed screw, an electric motor for rotating the tool spindle and the feed nut, transmission means for obtaining variable differential motion between the spindle and the feed nut to regulate the axial adjustment of the tool spindle relative to the feed nut and the supporting structure, and

means res onsive to the load on themotor for contro ling the transmission means.

,7. In an earth-borin system, a su porting structure, a tool spin le journalle in the supporting structure, a feed screw mounted on the spindle, a feed nut disposed to engage the feed screw, an electric motor for rotating the spindle and the feed nut and means responsive to the loadon the motor for adjusting the ratio of the speeds of rotation of the spindle and the feed nut to regulate the axial movement of the spindle.

8. In an earth-boring system, the combination with a rotary table and a work spindle dis osed to be rotated thereby, of a screw.- an -nut mechanism associated with the work spindle, means for securing'one element of the screw-and-nut mechanism to the work spindle, means for rotatably supporting another element thereof in fixed axial relation to the rotary table, an electric motor for rotating the rotary table, a variable-speed transmission mechanism operated by said motor for rotating the supporting element of the screw-and-nut mechanism to provide an adjustable differential motion between the elements thereof, and means responsive to the load on the motor for controlling the transmission mechanism.

In testimony whereof, I have hereunto subscribed my name this 23rd day of October,

FREDERIC W. HILD. 

